Directed well drilling



Feb. 26, 1952 D. B. GRABLE 2,586,939

DIRECTED WELL DRILLING Filed Nov. 12, 194e 2 SHEETS- SHEET 1 vow/ypzr YINVENToR.

ArroiP/yfz Feb. 26,1952 D. B. GRABLE DIRECTED WELL. DRILLING 2SHEETS-SHEET 2 Filed Nov. l2, 1946 JNVENToR.

Arf-WE1 m m M M y 0 M a www n( @as Patented Feb. 26, 1952 UNITED STATESPATENT OFFICE DIRECTED WELL DRILLING Donovan B. Grable, Long Beach,Calif. Application November 12, 1946, Serial No. 709,229 7 claims. (c1.c55-1.6)

This invention has to do with directional well drilling, andcontemplates within its general scope improved methods and equipment forconducting defiected drilling operations in a manner productive ofnumerous advantages distinguishing the invention from the past andconventional practices.

The customary procedures and tools used for directional or deflecteddrilling employ the usual whipstocks, i. e. deflective barriers set inthe Well and generally characterized by their open or exposed angulartop surfaces which, when engaged by the drill bits, deflect the latterin accordance with the whipstock orientation. Assuming this orientationto be correct, the accuracy of the bit or bore hole deflection islargely dependent upon the ability of the angular face of the whipstockto direct and maintain the bit in a. certain or predetermined course.

'Experience has shown that a given shape, extentor angularity of an openwhipstock deflecting face willv not always assure correspondingdeflection of the drill bit (or other formation cutting tool), becauseof the tendency of the bit to follow courses of least resistance in theformation, which may vary from the course directed by the whipstock. Forexample, while guided at one side by the whipstock, the bit mayencounter relatively softer formations in one or more differentdirections, and will tend to penetrate and deflect vlaterally of thewhipstock, or follow a course above that which the whipstock is intendedto establish.

One of my major objects is to provide not only for d-eflecting a bit orcutting tool in a predeterminable course, but also for so confining thetool or immediate portion of the drill string that the tool is guidedand confined in all directions laterally of its intended course ofadvancement and therefore given positive control With respect tof thecourse which it m-ust follow. Thus, with the guide orientationestablished, the bit cannot escape its intended cours-e, as for any ofthe reasons ordinarily responsible for error in the deflection, and thehole can be directed at any angle of defiection with complete accuracy.

More specifically, the invention contemplates providing at the properlocation in the well bore, an inclined passagewithin which the tool orbottom portion of the drill string is received and laterally confined inall directions so that upon advancement in a deiiected course determinedby the orientation .and angularity of the passage, the tool will bepositively fed and rigidly guided. Typically the angular guide passagemay be 2 l formed by a drillable tube contained or embedded in acementitious body of drillable material.

A 'further object of the invention is to so com bine or associate theabove mentioned guide passage with the drill string that setting andorientation oi the passage-containing body, and de` lected drilling mayoccur sequentially in a single operation, thus avoiding the expenditureof time, use of various tools, and multiple trips into and out of thewell, customarily required for a Whipstocking operation. In this respectthe inven-l tion contemplates lowering the guide passage body togetherwith the bit (While permitting downward uid circulation), and aftersetting and orienting the body, commencing defiect'ed drilling, all inAa single course of operation.

Particularly the invention aims to employ a novel association of theguide body with spaced pilot and main drill bits so that the pilot 'bitfirst is deflected to drill a bore to be followed by the main drill bit,and the latter then or simultaneously advances to drill away the guidebody and enter the pilot bore.

All the objects and advantages of the invention, as Well as the detailsof certain illustrative embodiments, will be fully understood from thefollowing' description of the accompanying drawings, in which:

Fig. l is a view taken in vertical section to show the guide bodylowered in the well on the pipe string to setting position;

Fig. 2 is a similar view showing the progression of the pilot bitthrough the guide into the formation;

Fig. 3 shows a further stage in the drilling progression after the mainbit has cut through the guide body;

Fig. 4 is a view similar to Fig. 1 illustrating a variational aspect ofthe invention; and

Fig. 5 is a fragmentary enlarged view illustrating a variational form ofreleasable connection between the guide body and the pipe string.

Referring first to Fig. l, the guide generally indicated at l0 is shownto be lowered and set in position at the bottom of the bore hole Ilwhich may lbe cased or uncased. The drill pipe string 'l2 is shown tocarry an upper or mainl drill bit throughcasing, milling'cutters ordrills may be used, or the bits may be made to penetrate casing.

Typically the guide I is shown to comprise a body I6 of cementitious orother non-magnetic drillable material having at its lower end an anchorplate or shoe I1 adapted to penetrate the sand or formation at thebottom of the hole, thuspreventing turning of the body from orientedposition. The body contains a tube I8 of nonmagnetic drillable metalcharacterized by its deviation from the vertical, and specificallyformed to have a straight upper portion I8a and a lower extent Ibextending angularly at an inclination desired for the intendeddeflection of the bit.

This angle of deflection may vary to serve the trative, the pipe I isshown to be' receivedwithin the body a' distance permitting receptionofthe pilot bit I4 in the' tube i8, and to be releasably heldI againstdownward movement relative' to" the body by means of shear pins I9carried by the body and received within openings 28 in the pipe fw i5.Suitable packing 2I`may engage about the pipe to confine the circulatingfluid against leakage through the top of the body.

As illustrative of `a variational' form of releasable connection betweenthe ldrill string and guide A:

tube body,Y Fig. 5 shows a threaded joint 22 typically in the form of aninsert 23 having right hand thread engagement with thethreaded porttion24 of the tube' section I5. After'the guide tube body is set inorientedpo'sition, the1joint at 22 may be broken by right-hand rotationof-ithe drill string, permitting downward rmovement-of the bits relativeto the guide.

In considering atypical offsets'drillingi-opera'- tion, 'assume the'guide'body assembly 'to be lowered to the bottom ofthe well on' thepipestring inthe described associationandrelation tothe bits I3 and I4shown in Fig. l. Itv'will be-ob- Aserved that the drill string and guidetube are in Aopen condition permitting maintenancevofdownward fluidcirculation during the loweringfopveration, a feature of advantageinpermittingtthe guide tube body to be circulated into setting position.Ordinarily it is desired to set thepl-ugata predetermined orientation,i. e. :a position at which the inclined portion I8b of the5 guide tubehas a determinable oriented direction. rFor this purpose I may lower online 25 through the pipe string and into a non-magnetic tube I8 anappropriate orienting instrument, conventionally indicated at 2'6 bywhich readings may be taken to establish the tube orientation.

With the drillable body and guide tube set in oriented position, thedrill string may be'lowered to release the described shear pin orthreaded connections, and advance the pilot bit I4 through the .guidetube, causing the bit to assume a correspondingly deflected course asillustrated in Fig. 2. The distance between the bits I3 and I4 may besuch that the pilot bit is permitted to drill the formation a more orless extended distance before bit I3 reaches the body I6, thuspreestablishing the direction and .inclination of the diverted drillhole before bit I3 commencesto cut away the body and tube assembly I0'.VUpon con- 4 tinued drilling, the pilot bit advances the bore 21 as bitI3 progressively cuts away the drillable material IB and guide tube,circulation at the time being continuously maintained through the drillstring to wash away the cuttings. Eventually bit I3 will have drilledthrough the guide tube body and may be permitted to penetrate theformation in a course following the direction of bore 21, whatever.depthdesired As illustrated inV Fig. 3, bit I3 may be permitted todrill the diverted bore 28 a distance sufficient to preestablish thedirection of drilling according to the course of the bore, whereupon thepipe string may be pulled to remove the pilot bit and tube I5.Thereafter drilling may be continued using the i single bit I3 whichwill follow the course of bore 28' andthe pilot bore 21.

Fig. 4 illustrates a variational procedure employing essentially thesame equipment as previously described, but differing in that the pilotbit is inserted within the angular guide tube 'before the assembly islowered in the well. Here the drillable body 29'i's shown to contain theangular guide tube 3G and packing 3l as before. The drill string 32'includes the upperbit. 33. a non-magnetic tube'section or pilot bitstring 34, and the pilot bit S5, the latter in thisinstance Vbeing shownas a closed endV bit, though having circulation openings 35, asdistinguished'from the core-type bit I4. Before lowering the assemblyinto the well, tube 34r and the pilot bit 35 may be thrust down into theguide'tube 30 to the'position illustrated and inzwhich the pilot bit andlower portion of .the tube 34 areA predeilected within the guide. Ifdesirable, areleasable connection may 'be'V effected .'betweeni theguide body and pipe string, as bymeans of a shear pin 31'interconnecting thepilot bit :and guide tube orbody. As before,circulationmay be maintained through theipipestring in the -operationofA setting the guide body. .The latter may be oriented by 'lowering online 33Y the instrument 39 to a position within the non-magnetic pilotbit Ystern and l'ower'angulanportion 30a of the guide tube. With thelatter oriented, drilling maybe commenced to progress inthe mannerpreviously described with the condition of the string-and guide assumingthe relationships illustrated in Figs. 2' and 3.

I claim:

1. In combination witha pipe Astring'carryng an upper largerdiameter-cutting tool and a lower pilot cutting tool, a body releasablyconnected `to said (pilot cutting tool and adapted tobe'loweredtherewith to setting position i'nthe well.

.said body containing a passage which in Yturn contains vsaid'pilot tooland is inclined fromi the vertical "and of sufficientisize to pass saidpilot cutting tool within thexbody and cause.- the 'tool to be deflectedlaterally intoA the formation, and a tubular connection between saidpilot tool and said upper cutting tool and'positioning the tools So thatfollowing deiiection of the pilot tool into the formation the upper toolengages and drills awaythe body as drilling progresses.

2. In combination with a pipe string carrying an upper largerv diametercutting tool, and a lower pilot cutting. tool, abody releasably-ccn-`nected Ato said pilot cutting tool'andadapted to be lowered therewithto setting position in the weil, Vsaid body containing a passage whichin turn contains said pilot tool and has downward and outward curvaturefroml the vertical to pass and deiiect said pilot cutting tool laterallyinto thev formation, and a tubular connection between said pilot tooland said upper cutting tool, said upper tool being positioned in thepipe string directly above the pilottool and being operable to cutawaythe material of said body after deection of said pilot tool into theformation.

3. In combination with a pipe string carrying an upper larger diametercutting tool and a lower pilot cutting tool, a body of drillablematerial releasably connected to said pilot tool to be lowered therewithto setting position in the well, a drillable tube in said body andinclined from the vertical, said pilot tool being retained within saidtube and movable therethrough to be deected laterally into theformation, and a tubular connection between said pilot tool and saidupper cutting tool and positioning the tools so that following deectionof the pilot tool into the formation the upper tool engages and drillsaway the body as drilling progresses.

4. In combination with a pipe string carrying an upper larger diametercutting tool and a lower pilot cutting tool, a body of drillablematerial connected to said pilot tool to be lowered therewith to settingposition in the well, a drillable tube in said body and inclined fromthe vertical, said pilot tool being retained within said tube, meansreleasably connecting said body and pilot tool against relative downwardmovement of the pilot tool, and a tube section conneiting said cuttingtools, said pilot tool being movable upon releasing said connectiondownwardly through said drillable tube to be deiiected thereby laterallyinto the formation and the upper tool being positioned in the string tothen engage and drill away the body.

5. In combination with a pipe string carrying an upper larger diametercutting tool and a lower pilot cutting tool, a body of drillablematerial releasably connected to said pilot tool to be lowered therewithto setting position in the well, a drillable tube extendinglongitudinally inside said body from the top to the bottom thereof andinclined from the vertical, a pipe section interconnecting said cuttingtools, downward uid circulation being maintainable from the pipe stringthrough said cutting tools. and inclined tube, said pilot tool beingreceived within and movable through said tube to be deflected therebylaterally into the formation and the upper tool being positioned `in thestring to then engage and drill away the body.

6. In combination with an oil well pipe string carrying an upper -largerdiameter ybit and a spaced lower pilot bit, tubing interconnecting saidbits, a body lowered to setting position in the well on said tubing andcontaining a longitudinal passage inclined from the vertical andcontaining said pilot bit, said passage being open to permit uidcirculation downwardly through the pipe string, tubing and body, andmeans releasably connecting the tubing and pilot bit with the body, saidbits being operable to sequentially pass the location of the body firstby movement of the pilot bit through said passage and then drilling ofthe body by said upper bit as the pipe string is lowered and the pilotbit is deected by said passage laterally into the formation. 7. Incombination with an oil well pipe string carrying an upper largerdiameter bit and a spaced lower pilot bit, tubing interconnecting saidbits, a body of cementitious drillable material lowered to settingposition in the well on said tubing and containing a longitudinalpassage inclined from the vertical and receiving said pilot bit, saidpassage being open to permit iluid circulation downwardly through thepipe string, tubing, and body, and means releasably connecting saidtubing and pilot bit with the body, said bits being spaced so that uponlowering of the pipe string the pilot bit is deected by said passagelaterally into the formation and the upper bit is then operable to drillaway the material of said body while following a course established bythe pilot bit deflection.

DONOVAN B. GRABLE.

REFERENCES CITED The following references are of record in the lile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,424,109 McBride July 25, 19222,043,381 Lane June 9, 1936 2,058,327 Lane Oct. 20, 1936 2,081,294Eastham May 25, 1937 2,119,746 Lane June 7, 1938 2,227,233 Scott et alDec. 31, 1940 2,281,414 Clark Apr. 28, 1942 2,334,747 Brantly Nov. 23,1943 2,498,159 Gammill Feb. 21, 1950 2,498,192 Wright Feb. 21, 1950

